Preoperative and Postoperative Care of Patients with Neurologic Disorders

Special Considerations for Deep Brain Stimulation

DBS is now a well-accepted treatment for medication-resistant Parkinson disease. Given the potential risk of intracerebral hemorrhage with insertion of DBS leads, all antiplatelet medications should be discontinued for 7 to 10 days prior to surgery. Typically, antiparkinsonian medications are discontinued the night before surgery. General anesthesia is avoided so that the patient is awake and parkinsonian symptoms can be monitored intraoperatively. Postoperatively, patients should be kept normotensive to minimize the risk of hemorrhage, and antiparkinsonian medications should be resumed immediately.

Movement-Disorder Emergencies in the Perioperative Period

Perioperative movement-disorder emergencies commonly occur because a patient’s usual medication regimen is discontinued or because of new medications introduced in the perioperative period. Diagnosis requires a detailed knowledge of the patient’s pre-existing conditions and a careful review of preoperative, intraoperative, and postoperative medications. Patients with Parkinson disease who have their levodopa discontinued suddenly may experience life-threatening parkinsonism-hyperpyrexia, characterized by fever, severe rigidity, autonomic instability, and an elevated serum creatine kinase level. Treatment includes restoration of dopaminergic therapy, and the management strategies discussed later.

Somewhat clinically similar to the parkinsonism-hyperpyrexia syndrome, neuroleptic malignant syndrome results from dopamine receptor blockade. Commonly implicated medications include neuroleptics, antiemetics (e.g., metoclopramide and prochlorperazine), and droperidol, which should be withdrawn promptly. In these syndromes, symptoms may last for days and be life-threatening. Treatment often requires care in the intensive care unit, with aggressive hydration and cooling. Dantrolene, bromocriptine, or amantadine is typically initiated, but the evidence for their efficacy is derived mainly from case reports.

A third and clinically distinct disorder, serotonin syndrome, results from excessive serotonin activity. It may occur as a consequence of drug interactions, overdose of certain medications, or therapeutic (or recreational) drug use. Though rare, of particular note is that patients with Parkinson disease taking monoamine oxidase B inhibitors (e.g., selegiline and rasagiline) are at risk for serotonin syndrome when combined with other serotonergic medications including some antibiotics and opiates (tramadol). Manifestations may include hypertension, tachycardia, hyperthermia, diaphoresis, myoclonus, tremulousness, hyperreflexia, confusion, agitation, and even coma. Treatment involves discontinuation of offending agents and often requires care in the ICU, control of the blood pressure, and management with cyproheptadine or benzodiazepines. A final related condition, discussed later, is malignant hyperthermia, a rare genetic disorder triggered by inhalational anesthetics or succinylcholine.

Delirium

Delirium is a complex entity characterized by the relatively acute onset of disorientation and attentional deficits that follow a fluctuating course. The incidence of postoperative delirium in the elderly ranges from 10 to 60 percent and varies somewhat with the type of surgery performed ( Table 54-1 ). Due to its variable forms—hyperactive, hypoactive, and mixed—delirium is often under-recognized. Hyperactive delirium involves agitation, combativeness, and hypervigilance, as is commonly seen in alcohol withdrawal. This form is easily recognized by clinicians. The hypoactive form, which may present with lethargy, stupor, or even coma, is sometimes difficult to recognize, as patients are less obtrusive and do not seek care or attention. It is not uncommon for these patients to be misdiagnosed with severe depression or for their cognitive dysfunction to be unrecognized.

Research has focused mainly on identifying baseline characteristics that predispose to the development of postoperative delirium and on iatrogenic risks of developing delirium, with relatively less emphasis until recently on the management and the long-term consequences of postoperative delirium. The vast majority of cases of postoperative delirium occur within 3 days of surgery and later onset delirium should raise concern for withdrawal from medications or alcohol. The consensus opinion is that the route of anesthesia, general versus regional, does not have a major impact on the rates of postoperative delirium. However, the type of anesthesia may be relevant when considering the timing of postoperative altered mental status. Patients receiving regional anesthesia tend to maintain or recover cognitive function more quickly than those receiving general anesthesia. Especially in the first 24 to 48 hours, it is important to consider which type of anesthesia the patient received as this may account for differences in mentation.

Factors that are associated with the development of delirium are well established ( Table 54-2 ). It is important to recognize the possibility of postoperative delirium in elderly patients and those with baseline cognitive impairment ranging from mild cognitive impairment to frank dementia. In patients undergoing elective surgery, it is especially important to obtain an accurate history of substance use as both intoxication and withdrawal may manifest as delirium following surgery. Even mild pre- to postoperative electrolyte shifts, such as subtle hypo- or hypernatremia, may result in postoperative delirium. Postoperative pain management poses a particular challenge. Both untreated pain and analgesic use may worsen delirium. There remains a tendency to utilize physical restraints postoperatively to prevent patients from disrupting their wounds; such restraints may increase the risk of delirium and therefore should be discontinued as soon as possible.

Postoperative delirium has been associated with a number of poor outcomes. Length of stay, postoperative complications, and mortality are known to increase in the setting of postoperative delirium. Such patients are more likely to be discharged to a rehabilitation or long-term nursing facility than those without delirium. It is important to remember that while delirium may only last a few days in many patients, a substantial number of patients will experience delirium that persists until hospital discharge or beyond. Postoperative delirium has also been associated with an increased risk of developing dementia in elderly patients with no known baseline cognitive dysfunction, suggesting that delirium may in itself cause long-term neurologic damage.

Prevention of postoperative delirium is critical, but if postoperative altered mental status develops, the focus should shift to early identification and exclusion of other potentially treatable causes. This workup usually includes neuroimaging to assess for stroke, hemorrhage, or mass lesion; an electroencephalogram (EEG) to evaluate for seizures; and possibly a lumbar puncture to evaluate for evidence of a cerebral inflammatory or infectious disorder. Treatment depends on identification and reversal of the underlying cause. In the postoperative period, delirium precautions should be instituted, including frequent reorientation, opening blinds to allow for natural light to enter, and maintaining normal sleep–wake cycles. Physical restraints should be discontinued as soon as is safe and replaced with close monitoring from nursing staff, sitters, or family members to ensure patient safety. Unnecessary lines and tubes, particularly urinary catheters, should be discontinued. Early postoperative mobilization, even range-of-motion exercises for bedbound patients, and simple acts such as making patients’ eyeglasses and hearing aids available are important in treating as well as preventing delirium. Psychoactive medications, particularly anticholinergics, should be discontinued whenever possible. Postoperative pain control should be with minimum levels of analgesics required for relief. If these nonpharmacologic interventions are insufficient, pharmacologic treatment should be considered only if patients pose a risk of direct harm to themselves or the staff, while taking care to avoid the benzodiazepine class of medications, which has a particularly poor cognitive side-effect profile. Common practice is to consider using a low dose of an antipsychotic medication, such as quetiapine, at bedtime.

Dementia

Patients with dementia who undergo surgery require special consideration. It is crucial to establish the patient’s preoperative baseline cognitive and physical function with family and caregivers in order to assess accurately their postoperative level of functioning. Patients with dementia are often elderly and have numerous medical comorbidities as well as poor nutritional status, dehydration, and baseline electrolyte abnormalities. These conditions should be optimized or corrected preoperatively in order to maximize recovery and shorten length of hospital stay. Acetylcholinesterase inhibitors used to treat dementia should be continued throughout the perioperative period, although this class of medications may prolong the effects of succinylcholine.

Patients with dementia are at an increased risk of numerous postoperative complications including renal failure, pneumonia, urinary tract infections, sepsis, and strokes. They also have an increased risk of postoperative delirium related to their baseline cognitive impairment and comorbidities.

Postoperative care for patients with dementia mostly revolves around the prevention and treatment of delirium. Pre- and postoperative consultation with geriatrics or neurology can be helpful, and when possible, patients with dementia should be cared for on hospital units that focus on acute care of elderly patients. Although surgery alone may be sufficient to precipitate delirium in a patient with dementia, other triggers should still be investigated. Patients with Alzheimer disease, and probably many other neurodegenerative conditions, are at increased risk of seizures, emphasizing the need to obtain an electroencephalogram for those with an unexplained altered mental state postoperatively. Postoperative pain control can be challenging as patients with severe dementia may not be able to verbalize whether they are in pain. Pharmacologic management of delirium in patients with dementia should be used as infrequently as possible. Benzodiazepines in particular should be avoided, and low-dose antipsychotics should be used sparingly—a US Food and Drug Administration black box warning links antipsychotics to increased mortality among elderly patients. In patients with Lewy body dementia, antipsychotics should be avoided due to their profound sedating and extrapyramidal effects, which may be irreversible. Patients with dementia and their families should be counseled early regarding the possibility of a prolonged postoperative hospital course and the potential for discharge to a rehabilitation or nursing facility; in the setting of elective surgeries, these considerations may impact the decision to proceed.